Disk device having real-time and reliability recording modes

ABSTRACT

A disk recording/reproduction device ideal for processing audio-visual data streams requiring real-time characteristics. A disk device has an operating mode ideal for recording and reproduction of motion image and audio data requiring real-time continuity by limiting the time needed for error processing, and the host incorporating the disk device can easily monitor the real-time continuity. The host can specify the urgency of individual recording and reproduction instructions to the disk so that control of real-time continuity can be actively implemented in better detail. A means for assigning a total number to a plurality of simultaneously recorded or reproduced data streams as well assigning individual data stream numbers allows informing the disk device of the throughput required by the host.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a data recording/reproductiondevice for recording and reproducing data of all types such as computerdata and relates in particular to random access type datarecording/reproduction devices. More specifically, the present inventionrelates to disk type data recording/reproduction devices utilized whilemounted in a host device such as a computer system and relates inparticular to disk type data recording/reproduction devices forrecording and reproducing for recording and reproducing computer datarequiring reliability, and video data and audio data requiring real-timecharacteristics.

[0003] 2. Description of the Related Art

[0004] All types of information processing systems such asgeneral-purpose computers contain a data recording/reproduction deviceto store large quantities of data and data for large scale applicationsin a non-volatile manner. Data recording/reproduction devices are forexample comprised of disk type devices to store data on a rotating diskand tape type devices to store data on wound reel of tape.

[0005] A typical disk device is the HDD or hard disk drive. The harddisk drive has an amazing data storage capacity due to advances made inmagnetic head technology and signal processing technology, etc. From1990 up to the present for example, the surface recording density ofdata has increased approximately 60 percent each year. One 3.5 inch diskis expected to be capable of recording 10 to 20 gigabytes of data sometime after the year 2000. In other words, one hard disk drive unithaving a plurality of disks would have a recording capacity in excess of100 gigabytes.

[0006] Therefore, by utilizing high efficiency digital moving picturecompression technology such as DV (digital video) or MPEG2 (MovingPicture Experts Group Phase 2) made practical in recent years, movingpicture information for a plurality of channels can be recorded on andreproduced from a hard disk drive, and multichannel video recorderscapable of using a hard disk drive as a recording medium are nowfeasible.

[0007] However, from a historical point of view the hard disk drive wasdeveloped as an external storage device for computers and technicalprogress has been made in improving so-called discrete text type dataand in making random access of data as fast as possible. In other words,hard disk drive operation is broken up or discrete along the time axis.

[0008] The computer system (hereafter “host”) incorporating the harddisk drive (HDD) issues commands (hereafter “host commands”) specifyingthe recording or reproduction of data. The operations in response toeach command from the host are executed one at a time as discreteoperations. Restated, the hard disk drive guarantees high reliabilitybut does not guarantee the recording or reproduction operation willfinish within a specified time (real time guarantee).

[0009] One cause that prevents guaranteeing the actual time required foran operation is the retry process. The recording and reproduction ofdata on a hard disk drive is performed in short data sector unit (forexample 512 bytes each) equivalent to the (information) packet used incommunications technology. In the retry process, an operation isrepeated again when an error occurs in implementing instructions such asto perform recording or reproduction. of a data sector assigned by thehost.

[0010] Various types of errors cause the retry operation to be used. Onsuch error is in the operation (seek) to move the head to the targetsector. To resolve the seek error, the recording and reproducing ontothat target sector must be abandoned and continued elsewhere or retryoperation must be performed. One retry requires from a few to severaldozen milliseconds of wasted time and is a factor in poor real-timecharacteristics. Next, is retries (Write-Retry) during recording ofdata. If a deviation in the head position exceeding the establishedtolerance occurs such as from mechanical shock applied for exampleexternally onto the hard disk drive during recording onto one datasector, then the recording operation will be halted. After waiting forthe head to be restored to a normal position and the head to once againcome to a position directly above the applicable sector by diskrotation, the recording of data onto the applicable sector starts onceagain (Write-Retry).

[0011] A third cause is retries (Read-Retry) during data reproduction(or playback). When an error is determined to occur that exceeds thecorrection capacity of the ECC (error correction code) in each sectorduring reproduction of one data sector, the operation stands by untilthe head once again comes to a position directly above the applicablesector by disk rotation and reproduction of the applicable sector startsagain (Read-Retry). Further, when determined that the error was notcorrected by one Read-Retry, a second Read-Retry is implemented. If theerror is not a soft error due for example to noise, but is a hard errordue definite cause such as damage of the magnetic film on the disk, thenRead-Retry might be attempted 10 times or more without correctly readingthe data, thus requiring at least 100 milliseconds of wasted time.Retries can therefore be a fatal problem in guaranteeing the actual timefor a recording/reproduction operation.

[0012] The maximum number of retries implemented and other such errorprocessing methods are fixedly incorporated into the design of relatedhard disk drives so that effective control according to the overallstatus of the disk recorder was not possible. Also, in the related art,a means was proposed for implementing or prohibiting retries withoutrestrictions (For example, in a portion of the interfaces standards, ofthe ATA (AT-Attachment) established by ANSI (American National StandardsInstitute)) however a means for setting a maximum allowable timerequired for error processing, or a means for dynamic control accordingto the urgency or criticality (namely, the real-time characteristics) ofrecording and reproduction were not proposed.

[0013] In the disk type data recording/reproducing device of the relatedart, it was also assumed that data files would be handled discretelyfrom each other so that instructions for recording or reproducing onindividual sectors were treated as mutually unrelated items. So inapplications such as multi-channel video and recorders with hard diskdrives, even when recording/reproducing with a small number of long AVdata streams, information on what data stream that the data for arecording/reproducing instruction belonged to was not utilized.

[0014] Therefore as related above, in the related art, the host deviceincorporating the disk type data recording/reproducing device had nosimple means for monitoring items such as the error processing time ofthe disk device. Consequently, the related art had the problem that thecontinuous real time required during the recording or reproducing ofinformation such as moving picture or audio information could not beguaranteed.

[0015] Still further, in the disk type data recording/reproducing deviceof the related art, the individual recording/reproducing operations wereimplemented without assigning a mutual rank or order (relation) so thata high throughput could not always be maintained.

SUMMARY OF THE INVENTION

[0016] In view of the above technical problems with the related art, thepresent invention therefore has the object of providing a disk type datarecording/reproducing device ideal for processing suited forrecording/reproducing of audio-visual data streams requiring real-timecharacteristics.

[0017] A further object of the present invention is to provide a disktype data recording/reproducing device ideal for maintaining thecontinuous real time characteristics for video recorders, and at thesame time improve the average data rate and the number of audio-visualdata streams capable of record/reproduction, and capable of high speedrecording/reproducing of high quality audio-visual data.

[0018] In view of the above technical issues, according to one aspect ofthe present invention, the disk type data recording/reproducing devicehas a first operation mode for recording or reproduction ofnon-continuous information and, a second operating mode for recording orreproduction of continuous information.

[0019] A typical example of the continuous information referred to hereis continuous image information compressed with the MPEG2 (MotionPicture Experts Group phase 2) method.

[0020] According to another aspect of the present invention, the disktype data recording/reproducing device has a first operation modestressing reliability of data more than real time characteristics ofrecording and reproduction and, a second operation mode stressing realtime characteristics more than the reliability of the data.

[0021] According to another aspect of the present invention, the disktype data recording/reproducing device comprises a disk as the recordingmedium, a record/reproduction section for recording and reproducing onthe disk, and an error processing section for recovery from errorsoccurring during the recording or reproducing on the disk, wherein thedisk type data recording/reproducing device has a first operation modewith a maximum allowable error processing time more than a specifiedvalue in the error processing section and, a second operation mode witha maximum allowable error processing time less than a specified value inthe error processing section.

[0022] The disk type data recording/reproducing device according toanother aspect of the present invention is connected to a host system byway of a host interface, and besides recording and reproducing on thedisk according to recording or reproducing commands received by way ofthe host interface, may be changed to the first operation mode or secondoperation mode according to a status change command received by way ofthe host interface.

[0023] The disk type data recording/reproducing device may also havemeans for actively performing an error processing procedure during theoperation mode without being restricted by error processing timecapacity, according to the urgency (criticality) for executing therecording or reproducing commands received by way the host interface.

[0024] The disk type data recording/reproducing device may also becapable of setting a large number of channels capable of simultaneousrecord or reproduction by using status change commands.

[0025] The disk type data recording/reproducing device according toanother aspect of the present invention comprises a disk as a recordingmedium, a recording/reproducing section for performing record orreproduction on the disk, and an error processing section for restoringoperation when an error occurs during recording or reproduction on thedisk,

[0026] wherein during recording a maximum allowable error processingtime can be set in the error processing section, and during reproductiona maximum allowable error processing time can be set in the errorprocessing section.

[0027] The disk type data recording/reproducing device according toanother aspect of the present invention is connected to a host system byway of a host interface, and besides recording and reproducing on thedisk according to recording or reproducing commands received by way ofthe host interface, a maximum allowable error processing time can be setby the error processing section according to status change commandsreceived by the host interface.

[0028] The disk type data recording/reproducing device contains meansfor actively changing the error processing procedure without beingrestricted by the maximum allowable error processing time, according tothe urgency (criticality) for executing the recording or reproducingcommands received by way of the host interface The disk type datarecording/reproducing device may also be capable of setting a maximumnumber of channels capable of simultaneous record or reproduction byusing status change commands.

[0029] The disk type data recording/reproducing device according toanother aspect of the present invention comprises a disk as a recordingmedium, a recording/reproducing section for performing recording orreproducing on the disk, an error processing section for restoringoperation when an error occurs during recording or reproduction on thedisk, and a buffer memory for temporarily storing recording orreproduction data,

[0030] wherein the disk type data recording/reproducing device furthercomprises means for setting a maximum number of channels capable ofsimultaneous record or reproduction according to commands from the hostand, means for changing internal data such as error processingprocedures and areas assigned to the buffer memory, according to themaximum number of channels.

[0031] The disk type data recording/reproducing device according toanother aspect of the present invention operates according to commandsfrom a host system connected byway of a host interface and comprises adisk as a recording medium, a recording/reproducing section forperforming recording or reproducing on the disk, and a buffer memory fortemporarily storing recording or reproduction data,

[0032] wherein said disk type data recording/reproducing device furthercomprises stream identifiers in recording or reproduction commandsreceived from the host showing the data stream that data for recordingor reproduction belongs to, and

[0033] further comprises control means for adaptably controllinginternal processing such as reference means for the buffer memoryaccording to the stream identifiers.

[0034] The disk type data recording/reproducing device according to thevarious aspects of the present invention is utilized while connected toan external host system by way of a host interface in conformance withATA (AT-Attachment) interface standards decided for instance by ANSI(American National Standards Institute) standards. One example of a hostsystem is a digital image disk recorder for recording and reproducingdata streams such as for video and audio data on the disk device of thepresent invention. The host system preferably utilizes a command setcapable of being processed by the disk device in an operating modelimited by a specified error processing time.

[0035] The present invention was contrived based on the fact that theneed for data reliability and for real time characteristics changeaccording to the type of data handled by the HDD.

[0036] For instance, data reliability is indispensable in order for ahard disk drive (HDD) to handle computer data. Computer data containingerrors is worthless for computer processing, and requires processingtime and error correction.

[0037] In contrast, when a hard disk drive (HDD) handles audiovisualdata, the recording and reproducing of data with real-timecharacteristics has the most importance and data reliability can besacrificed to some extent. The reason being that even if the reproducedaudio or video contains errors to some extent in the data, the limitedrange of human visual and audio perception allows those errors to beignored or compensated. However if the real-time characteristics cannotbe maintained, then the video or audio may intermittently cut off to anextent that cannot be ignored or compensated for, and the servicequality will drastically deteriorate.

[0038] The disk type data recording/reproducing device (hereafter,simply referred to as “disk device”) of the present invention, besideshaving an operation mode for recording or reproduction of non-continuousinformation (in other words, discrete information), further has anoperating mode for recording or reproduction of continuous information.The non-continuous information operation mode, hereafter referred to asIT (information technology) mode, is for handling data requiring highreliability such as computer data. The continuous information operationmode, hereafter referred to as AV (audio visual) mode, is for handlingdata requiring real time characteristics such as moving picture andaudio data.

[0039] The disk device of the present invention can be connected by wayof a host interface to a “host” such as a general-purpose computer or adigital motion picture recorder. This disk device further has a means toswitch operation modes by way of the host interface, and has a means toset the allowable error processing time during recording or reproductionaccording to the mode switching. Therefore, in this disk device, theallowable error time can be actively set for IT (information technology)mode when highly reliable discrete information is required, or for AV(audio visual) mode for continuous information that requires real timecharacteristics.

[0040] The disk device also contains information indicating the urgency(criticality) in the individual recording or reproducing commands. Thedisk device also has an instruction means to assign information toindividual data stream numbers and total channel numbers constituting aplurality of simultaneously recorded or reproduced data streams, andfurther has a means to change the operation inside the disk device basedon this assigned information.

[0041] The disk device of the present invention in other words,possesses operation modes for recording and reproduction of movingpicture data and audio data requiring real-time continuity, by means oflimiting the error processing time. The host incorporating the diskdevice can therefore easily control the real-time continuity.

[0042] The host can implement even finer active control of the real-timecontinuity by specifying the urgency (criticality) in the individualrecord/reproduction instructions to the disk device.

[0043] The host can also inform the disk device of the requiredthroughput by possessing a means to assign individual stream numbers andtotal channel numbers constituting a plurality of simultaneouslyrecorded or reproduced data streams. The disk device is thereforecapable of optimal internal processing such as data buffering.

[0044] Other objects of the invention, unique features and benefits willbecome apparent from the detailed description of the invention relatednext while referring to the accompanying drawings

BRIEF DESCRIPTION OF THE DRAWINGS

[0045]FIG. 1 is a block diagram showing the hardware structure of thedigital motion picture disk recorder incorporating the HDD 55 used asthe recording medium of the embodiment of the present invention.

[0046]FIG. 2 is a drawing showing the hierarchical structure of thefirmware implemented in the CPU-A27.

[0047]FIG. 3 is a diagram showing the relation of the GOP (Group ofPictures) defined in the MPEG2 data stream, and the clusters as unitsfor recording or reproducing data on the HDD 55.

[0048]FIG. 4 is a timing chart showing a typical operation of the HDD 55when recording only one data stream.

[0049]FIG. 5 is a timing chart showing typical operation in HDD 55 whenreproducing a channel 2 data stream, simultaneous with recording of achannel 1 data stream.

[0050]FIG. 6 is a timing chart showing typical operation in HDD 55 whensimultaneous recording three channels (in other words, Ch. 1, Ch. 2, andCh. 3).

[0051]FIG. 7 is a drawing showing an operation mode transition chart forthe HDD 55 of this embodiment.

[0052]FIG. 8 is a drawing showing an operation mode transition chart forthe HDD 55 of this embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] The embodiments of the disk device and the information processingsystem utilized in the present invention are explained next. Thefollowing embodiments are described by utilizing a typical fixed-typehard disk drive (HDD) as an example, however the present invention isnot necessarily limited to this type of hard disk drive. Other magneticdisk drives using a disk as the recording medium such as replaceablebubble HDD, floppy disk drives (FDD) or optical disk drives may ofcourse serve the same purpose in the present invention. It should alsobe understood that optical hard disk devices incorporating a floatingslider in the optical disk also may serve the same purpose in thepresent invention.

[0054] As one embodiment of the present invention, FIG. 1 is a blockdiagram showing the hardware structure of the digital moving picturedisk recorder incorporating HDD 55 as the recording medium. The digitalmoving picture disk recorder is capable of recording or reproduction ofdigital video information and audio information. Hereafter, each sectionis explained.

[0055] In FIG. 1, the digital motion picture recorder functions as the“host” for the HDD 55. In other words, one HDD 55 unit is connected tothe host by way of the host interface bus 30. The host interface bus 30may utilize standards such as expansion IDE (Integrated DriveElectronics) standards (equivalent to the previously mentioned ATAstandards of ANSI) as specifications. However, the present invention isnot restricted to a particular type of interface standard, and may forinstance utilize SCSI (small computer system interface) instead of theexpansion IDE specifications to achieve the same effect of theinvention.

[0056] The HDD 55 is configured to simultaneously record and/orreproduce compressed motion picture data and audio data on up to threechannels. Of these three channels, channel 1 (Ch. 1) and channel 2 (Ch.2) are supplied with motion picture (image) data and audio data beforecompression. Besides storing this data in the HDD 55 by MPEG2compression, the compressed motion picture data and audio data extractedfrom the HDD 55 is subjected to MPEG2 decompression (elongation) andoutput on a channel as a data stream. In contrast, channel 3 (Ch. 3)receives the motion picture (image) data and audio data aftercompression, and along with storing it in the HDD 55, transmits thecompressed data as is (without decompression) from the HDD 55 on achannel as a data stream.

[0057] The overall operation of this digital motion picture diskrecorder is coordinated by the CPU-A27. The CPU-A27 operates usingfirmware permanently stored in the ROM (Read Only Memory) 29, andutilizes the rewritable RAM (Random Access Memory) 28 as the operatingarea.

[0058] The digital motion picture disk recorder also has a userinterface structure (not shown in drawing) to accept user instructionsfor the recorder. The user interface structure is comprised for instanceof operating switches and buttons, remote controller, keyboard andliquid crystal display devices, etc.

[0059] The user inputs/output by way of the user interface structure arecontrolled by the CPU-A27 (or more specifically by firmware executed bythe CPU-A27). The user input/outputs include instructions for record orreproduction of motion picture (image) data and audio data in the HDD55. User input commands for the HDD 55 are implemented as instructionsissued by the CPU-A27 to the host interface 30 by way of the CPU-A bus26 and the AV I/F 25. Data exchange between the host and the HDD 55 isimplemented by the CPU-A27 issuing commands to the memory controlcircuit 23 and the AV I/F 25. The host does not exchange the transferreddata directly with the HDD 55 but temporarily stores it the host memory24.

[0060]FIG. 2 shows the hierarchical structure of the firmwarepermanently stored in the ROM 29. The firmware is implemented in theCPU-A27 as mentioned previously.

[0061] Functions to directly implement the hardware operation arepresent in the lower layer which is the first layer. In this layer, theuser I/F performs input/output in the user interface structure. TheMPEG2 encoder/decoder operation controller performs MPEG” encoder anddecoder processing for motion picture (image) data and audio data onchannel 1 and channel 2. The host memory controller writes and reads-outAV data streams and clusters in the host memory 24 specified by thememory controller 23. The HDD device driver sends and receives datacommands (host commands) to (and from) the HDD 55 by way of the hostinterface 30. The AV data stream processing host commands are defined inparticular defined for the present invention as is related later on.

[0062] The second layer controls the just described second layer, or inother words is the system control software (equivalent to so-called“operating system”) to control the overall operation of the digitalmotion picture disk recorder. The functions of the system controlsoftware include instruction and control of recording an reproductionoperation on each channel, finding and controlling the operating statusof hardware resources such as the HDD 55 and the host memory 24,functions required in the recorder and functions not contained in thefirst layer.

[0063] The flow of the recording signal during record throughout thedigital motion picture disk recorder is described next.

[0064] In Ch. 1, after the externally input analog image signal 1 (forinstance, NTSC (National Television System Committee) is digitized, thedata rate is compressed up to approximately one-fifth the original ratein the image information compressor 3. In this type of compressionmethod, the quantity of the original digital video information iscompressed by implementing methods such as discrete cosine conversion,frame motion detection, requantization, and two-dimensional bufferencoding. In the following description, the MPEG2 system is employed asthe video information compression method, and the data rate of the AVdata stream is 8 Mbps.

[0065] Simultaneous with the analog image signal 1, an analog audiosignal 2 is input externally, digitized and the data rate compressed bythe audio information compressor 4. The compressed video and audioinformation is multiplexed in the MUX5 and incorporated into the AV datastream.

[0066] The analog image signal 7 and the analog audio signal 8externally input in the Ch. 2 are in the same way, respectivelysubjected to image compression and audio compression, multiplexed andincorporated into the AV data stream.

[0067] The AV data streams from Ch. 1 or Ch. 2 are sequentially recordedin the host memory 27 temporarily, by way of the memory control circuit23. The CPU-A27 outputs instructions to the memory controller 23according to control implemented by the host memory controller fromamong the firmware, and reads out from the host memory 24 the datacluster (hereafter called “cluster”) for recording on the HDD 55, sendsthe data cluster to the HDD 55 by way of the AV-I/F25 and the hostinterface bus 30, and records it on a disk 49. In other words, the hostspecifies a recording or reproducing of data in clusters, on the HDD 55.

[0068]FIG. 3 is a diagram showing the relation of the GOP (Group ofPictures) defined in the MPEG2 data stream, and the clusters as unitsfor recording or reproducing data on the HDD 55.

[0069] One GOP is comprised of a consecutive I picture, B picture, and Ppicture to constitute an image of 15 frames (known art). In the exampleshown in FIG. 3, the clusters are data obtained from splitting a GOPinto four parts. One frame is equivalent to {fraction (1/30)}th of asecond so one GOP is equivalent to 0.5 seconds. The GOP data quantity is4 Mbits so the data size found from dividing a one second portion of adata stream by 8 is 1 Mbit.

[0070] The usual sector size in an HDD 55 in the computer field is 512bytes (or 4,096 bits) so that one cluster is equivalent to approximately245 sectors. In other words, when a record command is received from thehost (in other words, the motion picture data disk recorder) the HDD 55consecutively records approximately 245 sectors.

[0071] The operation of the HDD 55 during record is explained next. Tosimplify the explanation, an example is described for recording on onechannel, in other words only on the data stream from Ch. 1.

[0072] The CPU-A27 sends a host command (in this case a recordingcommand) to the HDD 55 to start recording of one cluster of data from aLBA (logic block address) consisting of a data block of specified lengthon the disk 49.

[0073] The hard disk controller 40 (hereafter “HDC”) inside the HDD 55is comprised of an input register for receiving commands and data fromthe host, and an output register for returning data and the statusinside the HDD 55 to the host. When the HDC 40 receives a recordingcommand from the host, the logic block address (LBA) specifying therecording command is converted to a physical address (The physicaladdress referred to here is for instance specified by a disk side No,track NO. or sector No.) inside the HDD 55 by means of mutual activeaction with the CPU-B42.

[0074] Next, the cluster sent from the host memory 24 is received in theinput register of HDC40 by way of the host interface bus 30, andtemporarily stored in the buffer memory 41. One cluster holds (asmentioned before) a data quantity equal for instance to 245 sectors. TheHDC40 divides up this received data into logic data sectors lengths (512bytes) set on the track of the disk 49, and further adds a preamblepattern and error correction codes around these track sectors forachieving bit synchronization during readout, and after being formedinto data sectors, is sent to the record channel circuit 51 insynchronization with the rotation of the disk.

[0075] The record channel 51 performs channel encoding of the datasectors and transforms the data into a binary train to match themagnetic record channel characteristics from the disk 49 and the head50. The recording amplifier 52 adds a rectangular record currentwaveform to this binary train (string), and the head 50 records it as aninverted magnetic pattern on the magnetic disk 49.

[0076] Positioning of the head 50 on the target track set beforehand forrecording is now necessary so the digital signal processor for servocontrol (servo DSP) 44 receives the target track No. from the HDC40 andCPU-B42, and while receiving the track No. on disk 49 from thereproduction channel circuit 53, the servo DSP 44 moves the head 50 tothat physical address and performs positioning.

[0077] In the above description, the time for used for recording onecluster is 125 milliseconds as shown in FIG. 4. The time required forseek and rotation standby (S1) on the HDD 55 and recording (W1) variesaccording to the speed of the HDD but is about 30 milliseconds. Theremaining time (125-S1-W1) becomes surplus time (E).

[0078] The flow of the reproduction signal in the overall digital motionpicture disk recorder is explained next.

[0079] The system controller software (mentioned previously) firstdesignates the name of the AV data stream for reproduction, according touser input information from the user I/F of the firmware. The systemcontroller software finds the logical block address (LBA) recorded witheach cluster constituting the data stream. The system controllersoftware issues a read-out instruction for the HDD device driver for thecluster to be read-out. The instruction issued by the HDD device driveris a host command defined on the host interface bus 30 (the expansionIDE interface in this embodiment). Simultaneous with issuing thisinstruction, the host memory controller maintains a recording area onthe host memory 24 for recomprising the cluster read-out.

[0080] The read-out instruction issued on the host interface bus 30, inother words the recording command defined on the expansion IDEinterface, is applied to the CPU-B42 inside the HDD 55 by way of theHDC40. The CPU-B42 converts the logical block address (LBA) of theapplicable cluster into a physical address (The physical address is forinstance specified by a disk side No, track No, and sector No., etc.)inside the HDD 55. The servo DSP44 commands the head 50 to move to thatphysical address, and start read-out of the required data. In otherwords, after the inverted magnetic pattern recorded on the magnetic disk49 is read-out by the head 50 and amplified by the reproductionamplifier 54, bit-synchronizing is performed by the reproduction channelsignal processor circuit 53, the binary data train (string) is detected,and decoding performed by inverse conversion of the channel encodingimplemented during recording, and then reproduced as a data sector.

[0081] The reproduced data sector is sent to the HDC40, error correctiondecoding performed and then sequentially stored in the buffer memory 41as logic data in 512 byte units. The buffered data is then sequentiallytransferred to the host memory 24 by way of the host interface bus 30and the memory controller circuit 23 and one cluster is formed. Whenread-out of one cluster is complete, the read-out of the next cluster iscommanded in the same way as previously described, and the subsequentcluster formed in the host memory 24.

[0082] The now formed cluster is sequentially sent from the host memory24, and supplied for example to the AV decoder 18 of Ch. 1 as an AV datastream. This AV data stream is separated into video data and audio databy the demultiplexer 17. When an error is present in the video data,interpolation processing is performed on data in front and behind by aninterpolator 15. Then, elongation (or decompression) into relateddigital image information is performed by the video informationdecompressor 13 and this related digital information output externally.This externally output image information is converted to an NTSC analogvideo signal 11 by means of a D/A converter, and supplied to an externalmonitor, etc.

[0083] The case when using only Ch. 1 was utilized for describing above,the flow of the compressed data recording and reproducing signals. Nexthowever, a description of the case when recording/reproducing aplurality of data streams containing data for Ch. 2 and Ch. 3 is alsogiven.

[0084]FIG. 5 is a typical timing chart showing the case when reproducinga Ch. 2 data stream, simultaneous with recording of a Ch. 1 data stream.

[0085] Only one head at time can operate in the HDD 55 so only onecluster can be recorded or reproduced at one time. Therefore, clustersfor two channels are alternately recorded or reproduced. In order forinstance, to access an area for recording the cluster (k, 1) of Ch. 1,seek and rotation standby (S1) is performed, and the cluster (k, 1)recorded. Next, seek and rotation standby (S2) is implemented toreproduce the cluster of Ch. 2, enclosing the surplus time (E). Thisseek operation is necessary because clusters on different channels areusually present in tracks of completely different diameters on the disk.Next, reproduction (R2) of cluster (k, 1) is set. This series of actionsis then repeated. In the example of FIG. 5, available time (E) remains,even if simultaneously recording/reproducing two channels on one HDD 55unit.

[0086]FIG. 6 is a timing chart showing simultaneous recording of threechannels (in other words, Ch. 1, Ch. 2, and Ch. 3). Three data streamsconsisting of a data stream generated by the Ch. 1 AV encoder from thehost side, a data stream generated by the Ch. 2 encoder, and a Ch. 3input data stream are sequentially recorded in the host memory 24 by thememory controller 23. These three data streams are split into respectiveclusters, and alternately recorded on the HDD 55 by write instructionson the host interface bus 30. The write instructions are host commandsspecified by the expansion IDE interface as the host interface.

[0087] The HDD 55 can only access one channel cluster at a time, thesame as the previously described two-channel simultaneous operation ofFIG. 5, so that recording of the three channels is performedalternately.

[0088] In the example shown in FIG. 6, the HDD 55 is busy using almostall the processing time for seek or recording or reproduction operation,and the surplus time (E) is extremely short. Obtaining a long surplustime (E) is difficult when the digital motion picture disk recorder issimultaneously recording/reproducing on the maximum number of channelsthat the speed of the HDD 55 allows.

[0089] The recording and reproduction operation of the digital motionpicture disk recorder was performed as described above. As the aboveexplanation clearly shows, the HDD 55 operation status varies dependingon the number of channels handled by the digital motion picture diskrecorder at that time. Namely, in the above recorder capable ofsimultaneous record/reproduction up to a maximum of three channels,though the HDD 55 only has a slight empty (surplus) time duringsimultaneous operation of these three channels, there is a considerableamount of empty time when operating on only one channel. Furthermore,during normal operation the disk recorder is almost never constantlyoperating on the maximum number of channels, and there are always timeswhen the disk recorder is operating on only a few channels. The systemcontroller software for the digital motion picture disk recorder knowsthe number of channels in simultaneous operation so the empty (surplusor available time) on the HDD 55 can be estimated.

[0090] Next, application of the HDD 55 to AV operation is described.

[0091] In Table 1 below, typical settings of the host interface commandsystem for different types of AV operation in the present invention areshown. In this command system, the vendor-unique instructions can bedefined, according to the ATA (AT attachment) standard (equivalent tothe expansion IDE standard) of ANSI. This instruction system ishereafter referred to as the AV command set. TABLE 1 COMMAND TYPESCOMMAND DESCRIPTION Set AV Send specified configuration data to diskconfiguration device, and change to AV mode. Read AV stream Reproducedata sector with limit on error processing time. Write AV stream Recorddata sector with limit on error processing time.

[0092] When for instance, a “Set AV Configuration” command is entered onthe host side (more specifically, CPU-A27 to run the HDD device driver)by way of the host interface bus 30, a specified parameter value is setin the internal register of the HDC40, and the disk device switches toAV mode (described later). Also, the “Read AV stream” and “Write AVstream” are respectively dedicated commands for record and reproductionof the AV data streams.

[0093] In this embodiment, the AV command set was vendor-unique commandsconforming to ATA standards but when standardized to normalizedcommands, even though the command No. changes, the functions may beconsidered essentially the same as in the present invention. Also, hostinterface standards other than ATA standards can also be defined for anAV command set having the same functions. In other words, there is nodependence on interface standards other than to impart a tangible formto the present invention.

[0094] The HDD 55 of this embodiment is comprised of two types ofoperating modes; the IT (information technology) mode and the AV (audiovisual) mode.

[0095] The IT mode is an operating mode suited for record orreproduction of non-consecutive (in other words, discrete) information.More specifically, the IT mode is a mode for performing roughly the sameoperations as a related HDD designed for recording and reproducing ofcomputer data. In the IT mode, data reliability is stressed rather thanreal-time continuity of record/reproduction, and no time limits are seton error processing. In other words, the IT mode is suited for handlingdata that requires high reliability, such as computer data.

[0096] The AV mode on the other hand, is an operation mode suited forrecord or reproduction of continuous information. More specifically, inorder to handle AV data consisting of video information and audioinformation, in recording or reproduction, the AV mode is an operationmode stressing real-time continuity rather than data reliability, andtime limits are set on error processing. In other words, the AV mode issuited for handling data requiring real-time characteristics such asmotion picture and audio data.

[0097]FIG. 7 and FIG. 8 are drawings showing operating mode transitiondiagrams for the HDD 55 of this embodiment. Hereafter, the operatingcharacteristics of the HDD 55 are explained while referring to thesetransition diagrams.

[0098] When the power is turned on, the HDD 55 first starts up in ITmode. The host (more specifically, the CPU-A27 running the HDD diskdriver) along with issuing a “SET AV CONFIGURATION” command (instructioncode 80h) to the HDD 55, can also command a transition to AV mode bysending “Set AV Configuration Data” (See FIG. 7). Also, after switchingto AV mode, the HDD 55 maintains AV mode as long as an AV command setsuch as “Read AV stream” or “Write AV stream” is continually used (SeeFIG. 8).

[0099] The respective data configurations for the input register insidethe HDC40 during issue of the “SET AV CONFIGURATION” command, and thecommand parameter data “Set AV Configuration Data” are shown in Table 2and Table 3 below. TABLE 2 Register 7 6 5 4 3 2 1 0 Features na SectorCount na Sector Number na Cylinder Low na Cylinder High na Device/Headobs na obs DEV na Command 80h

[0100] TABLE 3 Word Content 0 Bit 0 Mode 0 = IT mode 1 = AV mode Bits1-15 Reserved 1 Bit 0 Read continuous 0 = off 1 = on Bits 1-7 ReservedBits 8-15 Reserved 2 Reserved 3 Reserved 4 Total error recovery timelimit per READ AV STREAM command [ms] 5 Total error recovery time limitper WRITE AV STREAM command [ms] 6 Bits 0-3 Total number of streams Bits4-15 Reserved 7-255 Reserved

[0101] The instruction code for the “SET AV CONFIGURATION” is 80h, andas shown in Table 2, the instruction code 80H is written into thecommand register in the input register. Also, when a 1 is written intothe word 0 bit position of “Set AV Configuration Data” used for makingAV mode settings, the HDD 55 responds by switching to AV mode (switchesto IT mode if a 0 is in the bit position 0). Each time the “Set AVCONFIGURATION” command is issued, the HDD 55 switches to IT mode or AVmode according to whether a 0 or a 1 is present in the bit 0 position.

[0102] In IT mode, the recording or reproduction of computer data in theHDD 55 is specified by normal READ commands or WRITE commandsestablished in the related ATA standards.

[0103] In the AV mode however, the recording or reproduction of the AVdata stream in the HDD 55 is commanded by utilizing the “Read AV stream”command, and the “Write AV stream” command as shown in Table 1.

[0104] In AV mode, the passive parameter group required to execute thesetwo record/reproduction commands is set by the “Set AV ConfigurationData” shown in Table 3. In other words, during execution of the “Read AVstream” command in AV mode, the data contents of Word 4 are specified tothe HDD 55 in maximum allowable error processing (error recover timelimit) time in milliseconds. In the same way, during execution of the“Write AV stream” command in AV mode, the data contents of Word 5 arespecified to the HDD 55 in maximum allowable error processing (errorrecover time limit) time in milliseconds. Also, the data contents ofWord 6, are shown as the total number of AV data streams simultaneouslyrecorded or reproduced, utilizing the four bits of the bit positions, 0through 3.

[0105] When the host (more specifically, the CPU-A27 running the HDDdisk driver) sets the HDD 55 to AV mode, the HDC40 and the CPU-B42inside the HDD 55, store the maximum error processing time (errorrecovery time) when executing one “Write AV stream” command, accordingto the “Set AV Configuration Data” contents of word 5.

[0106] Causes of errors during execution of the record command, in otherwords, “Write AV stream” are seek errors on the track where the sectorfor recording is present, and an off-track head position due tovibration impacts during recording, and record head abnormalities duringrecording, etc. In the case of a seek error for instance, an errorprocessing (recovery) time of several milliseconds is required for thehead to re-seek to the target track after mistakenly arriving at anothertrack. In the case of an off-track or head abnormality, an errorprocessing (recovery) time including rotation standby time (forinstance, 11.1 msec when the rotation frequency is 90 Hz) is requiredsince the head 50 must retry recording of data after being in rotationstandby until once again arriving at the target sector.

[0107] During error recovery such as from an error occurring duringexecution of a record command, the CPU-B42 measures the time until errorprocessing is complete, with a timer. When the maximum error processing(recovery) time specified in “Set AV Configuration Data” is exceeded,that error processing is stopped, and operation shifts to the nextrecording or reproducing command. The real-time continuity of that nextrecorded or reproduced data is therefore maintained.

[0108] When the host has set the HDD 55 in AV mode, the HDC40 and theCPU-B42 inside the HDD 55, in the same way, store the maximumerrorprocessing (recovery) time when executing one “Read AV stream”command, according to the word 4 contents of “Set AV ConfigurationData”.

[0109] Seek errors on the track holding the target reproduction sector,and data detection errors during reproduction are listed as errorsoccurring during execution of the reproduction command or in otherwords, “Read AV stream”. The CPU-B42 uses a timer to measure the timefrom the occurrence of the error, until error processing is complete.When the maximum error processing (recovery) time specified in “Set AVConfiguration Data” is exceeded, that error processing is stopped, andoperation shifts to the next recording or reproducing command. Thereal-time continuity of that next recorded or reproduced data istherefore maintained.

[0110] Therefore, by setting an upper limit (threshold) for errorprocessing (recovery) time, when one error occurs requiring a long errorrecovery time and delaying execution of the next command, the aboveoperation satisfactorily prevents damage to the real-time continuity ofthe AV data stream.

[0111] The surplus (empty) time (E) during HDD 55 operation in thedigital motion picture disk recorder, as shown in FIG. 4, FIG. 5 andFIG. 6, fluctuates greatly according to the number of data base streamsfor simultaneous recording or reproduction, or in other words, thenumber of channels. The CPU-A27 on the host side is informed of thenumber of simultaneous record/reproduction channels by user instruction.Therefore, when a change in the number of simultaneousrecord/reproduction channels has occurred, a “SET AV CONFIGURATION”command is issued to the HDD 55, and the maximum error processing(recovery) time setting is readjusted according to the number ofchannels.

[0112] When for example, there are a large number simultaneousrecord/reproduction channels, the maximum error processing (recovery)time is shortened. Conversely, when the number of simultaneousrecord/reproduction channels is small, the maximum error processing(recovery) time is lengthened so that an optimum error processing timeis obtained while maintaining real-time continuity in the HDD 55.

[0113] In the above description, the “Set AV Configuration Data”parameter for the AV mode setting command for recording and reproductionhad a maximum error processing (recovery) time that was specified inmilliseconds. However other time units (such as microseconds) may beused for specifying and measuring time, and of course the same effect ofthe invention can be obtained.

[0114] Next, the current operating conditions of the digital motionpicture disk recorder such as the number of simultaneousrecord/reproduction channels are determined and a “SET AV CONFIGURATION”command is issued to the HDD 55. The measure taken when real-timecontinuity is difficult to maintain due to some kind of error occurringafter the AV data stream record or reproduction operation starts isexplained next.

[0115] For instance, if errors larger than expected by the hostcontinually occur during execution of continuous record or reproducingcommand, then the maximum allowable error processing time will be usedup trying to recover from these errors. In this kind of situation, theamount of reproduction data stored in the buffer memory 41 and the hostmemory 24 of the HDD 55 reaches zero, the average data rate required bythe AV decoder 18 cannot be maintained, and the motion picture imagequality deteriorates during reproduction (playback).

[0116] As one simple measure to improve this situation, a means isprovided to specify the urgency (criticality) for issue of individual AVrecord commands and AV reproduction commands, without newly issuing the“SET AV CONFIGURATION” command.

[0117] The data configuration in the input register inside the HDC40during issue of the “Read AV stream” command is shown in Table 4 below.TABLE 4 Register 7 6 5 4 3 2 1 0 Features URG DMA na Stream ID SectorCount Sector count Sector Number Sector number of LBA Cylinder LowCylinder number of LBA Cylinder High Cylinder number of LBA Device/Headobs LEA obs DEV Head number or LBA Command 81h

[0118] The instruction code for the “Read AV stream” command is 81h. Theinstruction code 81h is written into the command register inside theinput register as shown in Table 4.

[0119] The bit position 7 (URG) of the Features register bit in theinput register is defined as the Urgent bit to show the urgency (orcriticality) level of the command processing. The urgency level forexecuting that command is high when the bit URG is a 1. In this case,the maximum error processing (recovery) time setting with the “SET AVCONFIGURATION” command parameter is temporarily ignored, and the errorprocessing time is shortened as much as possible for that command'sreproduction operation. More specifically, only correction processingwith correction encoding requiring virtually no time is performed, andprocessing that requires time, such as retries are not performed. Thesemeasures allow the reproduction operation time to be shortened andallows avoiding critical situations that might harm the real-timecontinuity of the AV data stream.

[0120] When the quantity of reproduction data stored in the host memory24 reaches a sufficient level and the critical situation (urgent status)has been eliminated, the host sets this Urgent bit (URG) to 0 duringissued of the subsequent “Read AV stream” command. The error processingtime in the HDD 55 is thus reset to the maximum allowable error valuethat was previously set in the “Set AV Configuration Data” parameter ofthe “SET AV CONFIGURATION” command.

[0121] The data configuration of the input register inside the HDC40during issue of the “Write AV stream” command is shown in Table 5 below.TABLE 5 Register 7 6 5 4 3 2 1 0 Features URG DMA na Stream ID SectorCount Sector count Sector Number Sector number of LBA Cylinder LowCylinder number of LBA Cylinder High Cylinder number of LBA Device/Headobs LBA obs DEV Head number or LBA Command 82h

[0122] The instruction code for the “Write AV stream” command is 82h.The instruction code 82h is written into the command register inside theinput register as shown in Table 5.

[0123] The bit position 7 (URG) of the Features register bit in theinput register is defined as the Urgent bit to show the urgency (orcriticality) level of the command processing. The urgency level forexecuting that command is high when the bit URG is a 1. During recordingwith the disk recorder, the urgency level becomes high when the AVencoder output data stored in the host memory 24 exceeds a level thatcan be stored and overflows. When URG=1, error processing requiringtime, such as retries are not performed by the HDD 55. The data storedin the host memory 24 is thus speedily recorded in the HDD 55, andcritical situations (or urgent status) that halt the continuity of thedata stream can be eliminated.

[0124] The “Set AV Configuration” command sends the “Set AVConfiguration Data” parameter having the format shown in Table 3, to theHDD 55. The parameter, as previously related, shows the simultaneousrecord or reproduced AV data stream or in other words, the maximumnumber of channels, by using the four bits of bit positions 0 through 3of that word 6. By receiving that maximum number of channels from thehost, the HDD 55 can assign a widest possible memory (storage) areawithin the buffer memory 41, to each channel beforehand. The larger thecapacity of this buffer, the easier it is to maintain real-timecontinuity in the AV data stream, so the buffer capacity for eachchannel is made as large as possible.

[0125] When the host cannot inform the HDD 55 of the maximum number ofchannels, an optimal division of the buffer memory space cannot be madeon the HDD 55 side. The available memory area therefore cannot be usedeffectively, or the division of the memory area is smaller than thetotal number of channels to be handled so that data streams are presentwhich do not have their own memory area. The efficiency of data exchangewith the host then deteriorates and problems occur. Restated, the HDD 55of this embodiment is provided with a means to know the maximum (total)number of channels so that the above mentioned technical problems areresolved.

[0126] When the “Read AV stream” command and the “Write AV stream”command are issued as shown in Table 4 and Table 5, the host writes astream identifier (stream ID) in bit position 0 through 2 of theFeatures register in the input/output register. This stream identifier(stream ID) is a number especially for the data stream for recording orreproducing.

[0127] The HDD 55 utilizes this stream identifier to know what datastream or in other words, what channel the sector for recording orreproducing data belongs to. Therefore, the record data or thereproduction data can be stored in each correct respective memory(storage) area of the buffer memory 41 which is divided up into datastreams.

[0128] The CPU-B42 inside the HDD 55 checks whether or not dataspecified by a command is already present in the buffer memory 41. Ifdata specified by a command is present in the buffer memory 41, and ifan AV reproduction (playback) command, then the data in the buffermemory 41 is transferred to the host without loading it from the disk49. If the data is an AV record command, then the data is optimized forwriting onto the disk 49, or in other words, cache processing isperformed. When no stream identifier (stream ID) has been assigned, thecheck by the CPU-B42 is performed for the entire empty memory spaceinside the buffer memory 41 creating a large unwanted overhead in termsof command processing.

[0129] In the present invention, along with issue of a “Read AV stream”command, the stream identifier (stream ID) is also given so that a checkcan be made on the buffer memory 41 limited to the memory (storage) areacorresponding to the assigned stream identifier and related area so thatno check is made of the entire empty memory area of the buffer memory 41and the processing overhead can therefore be greatly reduced.

[0130] The present invention was described while referring to specificembodiments. However, as is clear to one skilled in the art, amendmentsor substitutions to the aforesaid embodiments may be made provided suchchanges are within the spirit and scope of the present invention.

[0131] The embodiment of the present invention for instance, wasexplained as a disk type data record/reproduction device suited for usein digital motion picture recorders, however the present invention isnot limited to use in digital motion picture recorders. The presentinvention may be satisfactorily adapted for instance, to disk type datarecord/reproduction devices connected to general-purpose computersystems by means of expansion IDE, SCSI or other interfaces.

[0132] In other words, the embodiments of the present invention are onlyintended as examples and should not be intended as limiting theinvention in any way. The section with the patent claims at thebeginning of these specifications patent claims should be referred to inorder to judge the meaning of the present invention.

[0133] The present invention as described above, provides a disk typedata record/reproduction device ideal for processing ofrecording/reproducing audio visual data streams requiring real-timecharacteristics.

[0134] The present invention also provides a disk type datarecording/reproducing device ideal for maintaining video recorder realtime characteristics, improving the average data rate and number ofaudio-visual data streams capable of simultaneous record/reproduction,and further capable of high speed recording/reproducing of high qualityaudio-visual data.

[0135] The present invention further provides a disk device havingoperation modes suitable for recording and reproduction of datarequiring real-time continuity by limiting the error processing time.Therefore, the host incorporating the disk device of the presentinvention can easily control the real-time continuity.

[0136] The present invention still further provides the effect that thehost can specify the urgency of individual record/reproductioninstructions to the disk device so that so that control of real-timecontinuity can be actively implemented in better detail.

[0137] Also in the present invention, the host can also inform the diskdevice of the required throughput by possessing a means to assignindividual stream numbers and total numbers constituting a plurality ofsimultaneously recorded or reproduced data streams. The disk device istherefore capable of optimal internal processing such as data buffering.

[0138] The disk device of the present invention unlike disk devicesdesigned to handle discrete data in ordinary computer applications, iscapable of suitable handling of real-time continuity information such asmotion picture and audio information. Therefore, by applying the diskdevice of the present invention to recording mediums such as videorecording devices, real-time continuity of data for recording andreproduction can be obtained. Furthermore, the throughput for datarecord and reproduction of the disk device can be improved so thateffects are obtained such as increasing the number of data streamssimultaneously handled such as by a video recording device or the imagequality can be enhanced by improving the average data rate.

What is claimed is:
 1. A disk recording/reproduction device comprising afirst operation mode for recording or reproduction of non-continuousinformation and, a second operating mode for recording or reproductionof continuous information.
 2. A disk recording/reproduction devicecomprising a first operation mode stressing reliability of data morethan real-time continuous recording and reproduction and, a secondoperation mode stressing real-time continuous recording and reproductionmore than the reliability of the data.
 3. A disk recording/reproductiondevice comprising a disk as the recording medium, a record/reproductionsection for recording and reproducing on the disk, and an errorprocessing section for recovery from errors occurring during therecording or reproducing on said disk, wherein said disk type datarecording/reproducing device has a first operation mode with a maximumallowable error processing time more than a specified value in saiderror processing section and, a second operation mode with a maximumallowable error processing time less than a specified value in saiderror processing section.
 4. A disk recording/reproduction deviceaccording to claim 3 connected to a host system by way of a hostinterface, wherein besides recording and reproducing on the diskaccording to the recording or reproducing commands received by way ofthe host interface, said disk recording/reproduction device alsoswitches between the first operation mode and the second operation modeaccording to a status change command received by way of the hostinterface.
 5. A disk recording/reproduction device according to claim 4,having means for actively performing an error processing procedureduring operation mode without being restricted by error processing timecapacity, according to the criticality for executing recording orreproducing commands received by way the host interface.
 6. A diskrecording/reproduction device according to claim 4, capable of setting alarge number of channels capable of simultaneous record or reproductionby using status change commands.
 7. A disk type datarecording/reproducing device comprising a disk as a recording medium, arecording/reproducing section for performing record or reproduction onthe disk, and an error processing section for restoring operation whenan error occurs during recording or reproduction on the disk, wherein amaximum allowable error processing time can be set in the errorprocessing section during recording, and a maximum allowable errorprocessing time can be set in the error processing section duringreproduction.
 8. A disk type data recording/reproducing device accordingto claim 7 connected to a host system by way of a host interface,wherein besides recording and reproducing on the disk according torecording or reproducing commands received by way of the host interface,a maximum allowable error processing time can be set by the errorprocessing section according to status change commands received by thehost interface.
 9. A disk type data recording/reproducing deviceaccording to claim 8, comprising means for actively changing the errorprocessing procedure without being restricted by the maximum allowableerror processing time, according to the criticality for executing therecording or reproducing commands received by way the host interface.10. A disk type data recording/reproducing device according to claim 8for setting a maximum number of channels capable of simultaneous recordor reproduction by using status change commands.
 11. A disk type datarecording/reproducing device operating according to commands from a hostsystem connected by way of a host interface and comprising a disk as arecording medium, a recording/reproducing section for performing recordor reproduction on the disk, an error processing section for restoringoperation when an error occurs during recording or reproduction on thedisk, and a buffer memory for temporarily storing recording orreproduction data, wherein said disk type data recording/reproducingdevice further comprises a means for setting a maximum number ofchannels capable of simultaneous recording or reproduction according tocommands from the host and, a means to change internal data such aserror processing procedures and areas assigned to the buffer memory,according to the maximum number of channels.
 12. A disk type datarecording/reproducing device operating according to commands from a hostsystem connected by way of a host interface and comprising a disk as arecording medium, a recording/reproducing section for performing recordor reproduction on the disk, and a buffer memory for temporarily storingrecording or reproduction data, wherein said disk type datarecording/reproducing device further comprises stream identifiers inrecording or reproduction commands received from the host showing thedata stream that data for recording or reproduction belongs to, andstill further comprises control means for adaptably controlling internalprocessing such as reference means for the buffer memory according tothe stream identifiers.
 13. A disk type data recording/reproducingdevice according to claim 4 connectable by way of said host interface,wherein said disk type data recording/reproducing device contains acommand set for processing in said second operation mode.
 14. A disktype data recording/reproducing device according to any one of claims 8,11 or 12 connectable by way of said host interface, wherein said disktype data recording/reproducing device contains a command set forprocessing in an operation mode having a maximum allowable errorprocessing time set within a specified value, during recording orreproduction.
 15. A disk type data recording/reproducing deviceaccording to claim 1, wherein said continuous information is continuousimage information compressed with the MPEG2 (Motion Picture ExpertsGroup phase 2) method.
 16. A disk type data recording/reproducing deviceaccording to any one of claims 4, 8, 11 or 12, wherein said hostinterface conforms to ATA (AT-Attachment) interface standards decided byANSI (American National Standards Institute).